is it fine to place current shunts parallel to obtain a value which you dont have or are shunts specialty resistors which cannot be paralleled up?

the cost is a bit more inaccuracy but Im not sure if shunts can be paralleled up since they are specialized resistors.

 

You can connect them in parallel just like you would resistors. Just take care to make the connection resistance as low as possible.

 

As dl324 alluded to, any small connection resistance can cause more current to go through one shunt as compared to the other (assuming they are equal resistance shunts), causing an inaccuracy if you are reading across only one of the shunts.
To minimize that, solder or connect the shunts closely together and then run the input and output current connections to the middle of the connections, not to one of the shunts ( like the diagram below) so that the connection distance from the I/O wires to each shunt is the same .

 

Then series is fine too?

Series is okay, but now you need to be concerned about the connection resistance between the two shunts, which can cause an error.
These external resistances are a problem since most shunt resistors have a very small value, comparable to the resistance to a short length of standard hookup wire.